A reaction of a thiol compound and a compound having a carbon-carbon double bond is known as a thiol-ene reaction, and an academic review has been reported in Non-Patent Document 1.
In the thiol-ene reaction, since a (meth)allyl compound and a thiol compound react in a functional group molar ratio of about one-to-one (1:1) to generate a thioether bond, a cured product with homogeneous functionality is achieved.
In addition, it has been known to be less susceptible to oxygen inhibition, and attention has been given to its excellent productivity as well as high flexibility and transparency.
In Patent Document 1, a thermosetting composition utilizing a thiol-ene reaction by a thermal polymerization initiator has been disclosed, and the suitability possibilities in the fields of coating agents such as coating materials, binders, adhesives, inks and the like have been described. In Patent Document 1, a thiol-ene cured product using a copolymer compound of (meth)acrylate compound and a primary thiol compound has been described. However, with the (meth)acrylate compound, since a homogeneous composition is not obtained because the homopolymerization of (meth)acrylic group per se is allowed to proceed with the thiol-ene reaction, elasticity and flexibility of the cured product may be insufficient.
In addition, in Patent Document 2, a photocurable resin composition for a lens sheet has been described, and a technique with regard to a thiol-ene cured product composed by a (meth)allyl compound and a primary thiol compound has been disclosed. However, an allyl compound having a molecular weight of not more than 300 has been used in the examples, and a thiol-ene cured product obtained by an ene oligomer having a large molecular weight has not been disclosed.
When using such ene compounds, it has been difficult to produce a cured product that can achieve all of sufficient flexibility, storage stability, solvent resistance, fracture resistance, elongation, and adhesion.